A method of obtaining linear frequency deviation in a wide-band frequency-modulation system

This report describes a method of obtaining linear frequency deviation in a wide-band frequency-modulation system. The primary cause of harmonic distortion in a frequency-modulation system is the non-linearity of the slope of the reactance valve. A method is described of linearizing this slope, and thereby obtaining very good linearity of the frequency modulation. The harmonic distortion is of the order of 60 db below the fundamental. This report also describes a method of checking high-fidelity frequency modulation.